无法使用 hive (CDH 5.9.0) 查询结构字段答案

【问题标题】：Can not query struct field with hive (CDH 5.9.0)无法使用 hive (CDH 5.9.0) 查询结构字段
【发布时间】：2017-05-06 14:04:54
【问题描述】：

我只是切换到 CDH 5.9.0（在新集群上进行全新安装，而不是升级）。我有一张像这样的表（有点复杂，但我也用这个例子重现）：

CREATE TABLE `products`(`header` struct<PCODE:string, PNAME:string>)
PARTITIONED BY (`IMPORT_DATE' string)
ROW FORMAT SERDE 
  'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe' 
STORED AS INPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetInputFormat'
OUTPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
LOCATION
  'hdfs://myhost.com:8020/user/hive/warehouse/dbp/products'
TBLPROPERTIES ('transient_lastDdlTime'='1482160314')

如果我这样做：

SELECT header FROM products;

==> 查询成功，返回所有产品标题（JSON格式）

但如果我这样做：

SELECT header.PCODE FROM products;

==> 失败并显示以下堆栈跟踪：

Error: java.lang.RuntimeException: Error in configuring object
                at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
                at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:75)
                at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
                at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449)
                at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
                at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:164)
                at java.security.AccessController.doPrivileged(Native Method)
                at javax.security.auth.Subject.doAs(Subject.java:422)
                at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1698)
                at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
Caused by: java.lang.reflect.InvocationTargetException
                at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
                at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:498)
                at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:106)
                ... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
                at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
                at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:75)
                at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
                at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
                ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
                at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
                at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:498)
                at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:106)
                ... 17 more
Caused by: java.lang.RuntimeException: Map operator initialization failed
                at org.apache.hadoop.hive.ql.exec.mr.ExecMapper.configure(ExecMapper.java:147)
                ... 22 more
Caused by: java.lang.NullPointerException
                at org.apache.hadoop.hive.ql.exec.ExprNodeFieldEvaluator.initialize(ExprNodeFieldEvaluator.java:61)
                at org.apache.hadoop.hive.ql.exec.ExprNodeFieldEvaluator.initialize(ExprNodeFieldEvaluator.java:53)
                at org.apache.hadoop.hive.ql.exec.Operator.initEvaluators(Operator.java:954)
                at org.apache.hadoop.hive.ql.exec.Operator.initEvaluatorsAndReturnStruct(Operator.java:980)
                at org.apache.hadoop.hive.ql.exec.SelectOperator.initializeOp(SelectOperator.java:63)
                at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:385)
                at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:469)
                at org.apache.hadoop.hive.ql.exec.Operator.initializeChildren(Operator.java:425)
                at org.apache.hadoop.hive.ql.exec.TableScanOperator.initializeOp(TableScanOperator.java:193)
                at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:385)
                at org.apache.hadoop.hive.ql.exec.MapOperator.initializeOp(MapOperator.java:431)
                at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:385)
                at org.apache.hadoop.hive.ql.exec.mr.ExecMapper.configure(ExecMapper.java:126)
                ... 22 more

在我的旧集群 (CDH 5.8.2) 上，它运行良好。有什么想法吗？

[编辑：我已将所有 CDH 5.9.0 jar (/opt/cloudera/parcels/CDH/jars) 降级为 CDH 5.8.2 并且查询成功。 CDH 5.9.0 中可能存在回归...]

[编辑 2：如果表存储为 TextFile ('org.apache.hadoop.mapred.TextInputFormat')，则查询运行成功。我们可以认为问题与镶木地板有关。]

[也在Cloudera论坛发帖：https://community.cloudera.com/t5/Batch-SQL-Apache-Hive/Can-not-query-struct-field-with-hive-CDH-5-9-0/m-p/48672#U48672]

【问题讨论】：

标签： hadoop hive cloudera-cdh

【解决方案1】：

我将通过降低查询元素的大小写来解决此问题。例：

从产品中选择 header.pcode；

【讨论】：

Thx 但它不起作用......但给我一个线索:) 我会在几分钟内添加一个答案（即：使用 PARQUET 和 CDH 5.9 时避免在结构字段名中使用大写.0).
只有当结构字段名是小写时才有效。但是，如果它们是大写字母，它总是会失败。

【解决方案2】：

所以我尝试了很多东西，最终得到了以下结果：

-- Struct fieldnames in lowercase
CREATE TABLE `products`(`header` struct<pcode:string, pname:string>) STORED AS PARQUET;

选择结果：

SELECT header.pcode FROM products ==> 好的
SELECT HEADER.pcode FROM products ==> 好的
SELECT header.PCODE FROM products ==> KO
SELECT HEADER.PCODE FROM products ==> KO

-- Struct fieldnames in UPPERCASE
CREATE TABLE `products`(`header` struct<PCODE:string, PNAME:string>) STORED AS PARQUET;

选择结果：

SELECT header.pcode FROM products ==> KO
SELECT HEADER.pcode FROM products ==> KO
SELECT header.PCODE FROM products ==> KO
SELECT HEADER.PCODE FROM products ==> KO

==> 在 CDH 5.9.0 中存储为 PARQUET 的表的结构字段名中避免使用大写（在 CDH 5.8.2 中有效）...

【讨论】：